A lithographic system including a lithographic apparatus with an anamorphic projection system, and a radiation source configured to generate an EUV radiation emitting plasma at a plasma formation location, the EUV radiation emitting plasma having an elongate form in a plane substantially perpendicular to an optical axis of the radiation source.

An optical system has an aperture device having a multiplicity of aperture elements for the delimitation of the cross section of a ray bundle running through the optical system. The aperture device has a first aperture element, which is pivotable about a first rotation axis between an engagement position in the beam path of the optical system and a neutral position outside the beam path of the optical system and has a first aperture opening delimited by a first aperture edge. The aperture device also has at least one second aperture element, which is pivotable about a second rotation axis between an engagement position in the beam path of the optical system and a neutral position outside the beam path of the optical system and has a second aperture opening delimited by a second aperture edge. The second aperture opening is smaller than the first aperture opening. The aperture elements pivoted into the engagement position form an effective aperture opening. The aperture edges of aperture elements pivoted into the engagement position do not lie in a common plane.

There is provided a reflective imaging optical system forming an image of a first plane onto a second plane, wherein the numerical aperture with respect to a first direction on the second plane is greater than 1.1 times a numerical aperture with respect to a second direction crossing the first direction on the second plane. The reflecting imaging optical system has an aperture stop defining the numerical aperture on the side of the second plane, and the aperture stop has an elliptic-shaped opening of which size in a major axis direction is greater than 1.1 times that in a minor axis direction. The reflective image-forming optical system is applicable to an exposure apparatus using, for example, EUV light and capable of increasing numerical aperture while enabling optical path separation of light fluxes.

An imaging optical unit for projection lithography has a plurality of mirrors for imaging an object field into an image field with imaging light guided along a path from the object field to the image field. The penultimate mirror in the path has no passage opening to pass the imaging light. The imaging optical unit has a stop to predefine an outer marginal contour of a pupil of the imaging optical unit. The stop is between the penultimate and last mirrors in the path. The imaging optical unit can have exactly one stop for predefining at least one section of the outer pupil marginal contour. An entrance pupil of the imaging optical unit can be upstream of the object field. The imaging optical unit can be well defined regarding its pupil and exhibit desirable properties for projection lithography.

A method and system for: forming a first rectangular shape with photomask writing equipment, using a first sub-threshold dosage on a photoresist layer of a photomask substrate; forming an overlapping second rectangular shape with the photomask writing equipment using a second sub-threshold dosage on the photoresist layer, the second rectangular shape being rotated relative to the first rectangular shape to form one of: a hexagonal overlap area and an octagonal overlap area, that exposes the photoresist layer to at least a threshold dosage; and forming a photomask, based on developing the exposed photoresist layer, to provide optical transmission corresponding to the one of: the hexagonal overlap area of at least the threshold dosage and the octagonal overlap area of at least the threshold dosage, for use by a photolithography system to write any of a contact, a via, or a curvilinear shape on an integrated circuit substrate.

A method and system for: forming a first rectangular shape with photomask writing equipment, using a first sub-threshold dosage on a photoresist layer of a photomask substrate; forming an overlapping second rectangular shape with the photomask writing equipment using a second sub-threshold dosage on the photoresist layer, the second rectangular shape being rotated relative to the first rectangular shape to form one of: a hexagonal overlap area and an octagonal overlap area, that exposes the photoresist layer to at least a threshold dosage; and forming a photomask, based on developing the exposed photoresist layer, to provide optical transmission corresponding to the one of: the hexagonal overlap area of at least the threshold dosage and the octagonal overlap area of at least the threshold dosage, for use by a photolithography system to write any of a contact, a via, or a curvilinear shape on an integrated circuit substrate.

An super-resolution system for nano-patterning is disclosed, comprising an optical printing head that enables a super-resolution lithographic exposures compatible with conventional optical lithographic processes. The super-resolution exposures are carried out using light directed onto a medium using plasmonic structures, and in particular using plasmonic structures using specially designed super-resolution apertures, of which the bow-tie and C-aperture are examples. These specially designed apertures create small but bright images in the near-field transmission pattern. A printing head comprising an array of these apertures is held in close proximity to a medium for patterning. In some embodiments, a data processing system is provided to re-interpret the data to be patterned into a set of modulation signals used to drive the multiple individual channels and the multiple exposures.

There is provided a reflective image-forming optical system which is applicable to an exposure apparatus using, for example, EUV light and which is capable of increasing numerical aperture while enabling optical path separation of light fluxes. In a reflective imaging optical system (6) forming an image of a first plane (4) onto a second plane (7), the numerical aperture on a side of the second plane with respect to a first direction (X direction) on the second plane is greater than 1.1 times a numerical aperture on the side of the second plane with respect to a second direction (Y direction) crossing the first direction on the second plane. The reflecting imaging optical system has an aperture stop (AS) defining the numerical aperture on the side of the second plane, and the aperture stop has an elliptic-shaped opening of which size in a major axis direction (X direction) is greater than 1.1 times that in a minor axis direction (Y direction).

A method for improving imaging of a feature on a mask to a substrate during scanning operation of a lithographic apparatus. The method includes obtaining a dynamic pupil representing evolution of an angular distribution of radiation exposing a mask during a scanning operation of a lithographic apparatus and determining a variation of shift of a feature at a substrate during the scanning operation due to interaction of the dynamic pupil with the mask. The method includes configuring a mask parameter and/or or a control parameter of the lithographic apparatus to reduce the variation of shift of the feature.

An imaging optical unit for EUV projection lithography serves to image an object field into an image field. Mirrors guide imaging light from the object field to the image field. An aperture stop is tilted by at least 1 in relation to a normal plane which is perpendicular to an optical axis. The aperture stop has a circular stop contour. In mutually perpendicular planes, a deviation of a numerical aperture NA.sub.x measured in one plane from a numerical aperture NA.sub.y measured in the other plane is less than 0.003, averaged over the field points of the image field. What emerges is an imaging optical unit, in which homogenization of an image-side numerical aperture is ensured so that an unchanging high structure resolution in the image plane is made possible, independently of an orientation of a plane of incidence of the imaging light in the image field.